U.S. Environmental Protection Agency Clean Air Scientific Advisory Committee (CASAC) Sulfur Oxides Panel Public Meeting Review of the Integrated Science Assessment for Sulfur Oxides – Health Criteria External Review Draft John Vandenberg, Steve Dutton, and Tom Long National Center for Environmental Assessment, Office of Research and Development Raleigh, NC, January 27-28, 2016
NAAQS Review Process Workshop on Integrated Review Plan (IRP) : timeline and key science-policy issues policy-relevant issues and scientific questions Integrated Science Assessment (ISA) : evaluation and Peer-reviewed synthesis of most policy-relevant studies Clean Air Scientific scientific studies Advisory Committee (CASAC) review Risk/Exposure Assessment (REA): Call for quantitative assessment, as warranted, focused Public comment information on key results, observations, and uncertainties Policy Assessment (PA): staff analysis of policy options based on integration and interpretation of information in the ISA and REA EPA Agency decision proposed Interagency making and draft decisions on review proposal notice standards Public hearings Agency decision EPA final Interagency and comments making and draft decisions on review on proposal final notice standards 1
Documents Informing the Review of the Primary SO 2 NAAQS • Integrated Review Plan (IRP) ( completed October 2014 ) – Provides an orientation for the new CASAC Panel regarding the history of the past reviews, decisions, and any relevant litigation – Highlights key policy-relevant science issues that will guide review – Outlines process and schedule for review – CASAC Panel reviewed and commented on the IRP in April 2014 • Integrated Science Assessment (ISA) – Concise evaluation and synthesis of the most policy-relevant science – Emphasis on integration of the science and on clear characterization of strengths and uncertainties of available scientific evidence – ISA provides the scientific foundation for … • Risk and Exposure Assessment • Policy Assessment • Agency decisions as reflected in proposed and final rules – CASAC reviews and comments on the ISA • Meetings are open to the public and include opportunities for public 2 comments
Documents Informing the Review of the Primary SO 2 NAAQS (cont.) • Risk and Exposure Assessment (REA) – Prior to conducting an assessment, EPA prepares an REA planning document to assess the degree to which new evidence and tools support conducting a new quantitative REA • If an REA is warranted, the planning document also describes the scope and methods plan for the assessment • EPA consults with CASAC on the REA planning document – The REA, if warranted, draws upon information and conclusions presented in the ISA to develop quantitative characterizations of exposures and associated risks to human health associated with recent air quality conditions and with air quality estimated to just meet the current standard(s) and, if appropriate, alternative standard(s) under consideration – The REA, if warranted, includes a characterization of the uncertainties associated with such estimates – CASAC reviews and comments on draft REAs, if conducted • Meetings are open to the public and include opportunities for public comments 3
Documents Informing the Review of the Primary SO 2 NAAQS (cont.) • Policy Assessment (PA) – Provides a transparent staff analysis of the scientific basis for alternative policy options for consideration by senior management prior to rulemaking – Intended to help “bridge the gap” between the Agency’s scientific assessments, presented in the ISA and REA(s), and the judgments required of the EPA Administrator in determining whether it is appropriate to retain or revise the NAAQS – Focuses on the information most pertinent to evaluating the basic elements of the NAAQS: indicator, averaging time, form, and level – CASAC reviews and comments on draft PA • Meetings are open to the public and include opportunities for public comments 4
Framework for Causal Determination • Promote consistency and transparency • Emphasize synthesis of evidence across scientific disciplines (e.g., controlled human exposure, epidemiologic, and toxicological studies) • Weight of evidence for causal determination – Causal relationship – Likely to be a causal relationship – Suggestive but not sufficient to infer a causal relationship – Inadequate to infer the presence or absence of a causal relationship – Not likely to be a causal relationship • ISA Preamble describes this framework –Preamble is now stand-alone document (http://www.epa.gov/isa) • CASAC has supported use of this framework in past ISAs 5
Causal Framework Description Causal Evidence is sufficient to conclude that there is a causal relationship with relevant relationship pollutant exposures (e.g., doses or exposures generally within one to two orders of magnitude of current levels). That is, the pollutant has been shown to result in health Rule out chance, confounding, and effects in studies in which chance, confounding, and other biases could be ruled out other biases with reasonable confidence. For example: (1) controlled human exposure studies Consistency, coherence, biological that demonstrate consistent effects; or (2) observational studies that cannot be plausibility, high-quality studies explained by plausible alternatives or that are supported by other lines of evidence (e.g., animal studies or mode of action information). Generally, the determination is based on multiple high-quality studies conducted by multiple research groups. Likely to be Evidence is sufficient to conclude that a causal relationship is likely to exist with a causal relevant pollutant exposures. That is, the pollutant has been shown to result in health Multiple, high-quality studies show relationship effects in studies where results are not explained by chance, confounding, and other effects biases, but uncertainties remain in the evidence overall. For example: (1) Some uncertainty remains overall observational studies show an association, but copollutant exposures are difficult to address and/or other lines of evidence (controlled human exposure, animal, or mode of action information) are limited or inconsistent; or (2) animal toxicological evidence from multiple studies from different laboratories demonstrate effects, but limited or no human data are available. Generally, the determination is based on multiple high-quality studies. Suggestive Evidence is suggestive of a causal relationship with relevant pollutant exposures, but Cannot rule out chance, but not is limited, and chance, confounding, and other biases cannot be ruled out. For confounding, other biases sufficient to example: (1) when the body of evidence is relatively small, at least one high-quality -Evidence is limited but supporting infer a epidemiologic study shows an association with a given health outcome and/or at -Evidence is sizeable and generally causal least one high-quality toxicological study shows effects relevant to humans in animal relationship species; or (2) when the body of evidence is relatively large, evidence from studies but not entirely consistent of varying quality is generally supportive but not entirely consistent, and there may be coherence across lines of evidence (e.g., animal studies or mode of action information) to support the determination. Inadequate Evidence is inadequate to determine that a causal relationship exists with relevant Evidence is of insufficient quantity, to infer a pollutant exposures. The available studies are of insufficient quantity, quality, quality, consistency causal consistency, or statistical power to permit a conclusion regarding the presence or relationship absence of an effect. Not likely to Evidence indicates there is no causal relationship with relevant pollutant exposures. be a causal Several adequate studies, covering the full range of levels of exposure that human Multiple studies consistently show relationship beings are known to encounter and considering at-risk populations and lifestages, no effect are mutually consistent in not showing an effect at any level of exposure. 6 Excerpt from Table II of Preamble to the ISA
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